During the early morning
hours of March 9, 1957, a magnitude 8.3 earthquake struck along a section
of the Aleutian Trench located south of the Andreanof Islands (the section
of the Aleutian Islands shown above). The vertical seafloor displacement
that accompanied this quake generated a major Pacific-wide tectonic tsunami,
similar to the 1946 Aleutian event, but fortunately smaller. The 1957
event is not as well documented as that of 1946, which is probably do
to the fact that it struck hardest at the sparsely populated Aleutian
Islands, while more populated areas, such as Hawaii and California, received
smaller waves.

Effects at the
Aleutian Islands

Though the only reported
casualties across the Aleutian Islands were sheep, the tsunami did generate
some impressive wave heights, as shown on the map above (black triangles).
Eight-foot waves struck at Adak Island. The tsunami destroyed houses and
boats at the harbor of Atka Island. Wave heights reached 40 feet near
the Scotch Cap Lighthouse at Unimak Island, and were reportedly up to
75 feet high on the Pacific side of Umnak Island. As was the case with
tsunami of 1946, the Aleutian Islands shielded the Alaskan mainland from
the effects of the tsunami.

Effects at Hawaii

Unlike the situation during 1946, this
time the Hawaiian Islands received advanced warning of the approaching
tsunami, which provided Hawaiian authorities with sufficient
time to spread the warning, and evacuate low lying areas. As
a result, there were no fatalities directly associated with the
1957 tsunami. The damage caused by the tsunami to the Hawaiian
Islands as a whole was also less than that of 1946, due to the
fact that in general, the 1957 tsunami waves were smaller than
those of 1946, especially at densely populated areas such as
the city of Hilo.

At Hilo, on the Island of Hawaii, tsunami
runup was 10 feet above sea level. Many buildings along unprotected
section of the shore at Hilo were badly damaged by the waves,
but the downtown area was mostly spared due to the presence of
the coastal barrier and parkway, which buffered downtown Hilo
against the tsunami. This time damages at Hilo totaled only 150,000
dollars.

Other Islands in the Hawaiian chain however,
were not as lucky as Hawaii. Damage to the island of Kauai, where
the tsunami runup reached 32 feet above sea level, was greater
than that produced by the 1946 tsunami. The tsunami destroyed
boats and homes at the Island of Maui, where tsunami runup reached
23 feet above sea level at Waimea Bay.

Effects at the
United States West Coast

The tsunami of 1957 was
noticed in several locations along the Pacific coast of the United States,
but caused little damage, and no fatalities. Crescent City, California,
recorded an amplitude of 1.3 feet. Port Hueneme reported a 3.5-foot maximum
wave height. Shelter Island in San Diego was struck by a three-foot surge,
which damaged boats and docking facilities.

Effects at Other
Pacific Locations

The 1957 Aleutian tsunami
was recorded as a ten-foot surge at the Marquesas Islands of French Polynesia,
and also struck Chile as a six-foot wave.